The overall aim of this research application is to investigate the relationship of early problem identification and linkage to behavioral health care with later development of substance abuse and psychological injury outcomes and attrition from the armed services. This observational study is based on a quasi-experimental design with longitudinal data files and statistical models of deployment-related factors and military health services on the odds of long-term poor substance abuse outcomes, poor psychological outcomes (e.g. post-traumatic stress disorder, depression), thoughts of harmful behavior, and attrition from the Army, associated with service in Operation Enduring Freedom (OEF) or Operation Iraqi Freedom (OIF). We will form a cohort of Army members (active-duty and Reserve component) with deployments ending in FY2008-2010. Outcomes will be tracked, starting at 12 months through 24 months, for all cohort members and 36 months for early cohort entrants. We will compare the outcomes of a group that receives early treatment initiation and engagement among the OEF/OIF cohort to a comparison group from the cohort (weighted for trauma exposure and self-report problems using propensity scores) that does not receive early treatment initiation and engagement. We also will compare the outcomes for the OEF/OIF returnee group that a military health system (MHS) professional identifies and refers early for follow-up assessment to a group from the cohort with self-report of potential problems (weighted using propensity scores) without early identification and referral. The role of this early identification and referral (within two months of return), and this early linkage to treatment (within 5 months of return) will be the primary focus of the analysis. We will merge MHS and Veterans Administration (VA) data for the cohort members to form complete longitudinal files previously unavailable for analyses, with observations of veterans' delayed problem presentation and service utilization in both health systems, and long-term adverse substance abuse and psychological outcomes and attrition from the Army. We also will be able to describe and better understand which combat veterans seek care from the VA among all that are eligible, as VA statistics suggest that 35% or fewer of OEF/OIF are using VA services to which they are entitled. The findings will provide operationally actionable data useful to quality improvement programs in the MHS and VA on urgent issues requiring clinical and policy attention.